The great revolving door between Washington and Wall Street keeps spinning. This week’s news that former Federal Reserve Chairman Ben Bernanke has signed on to be an adviser at a $25 billion hedge fund, Citadel, is just the latest example of this sad practice.

It’s hard to get too angry at Bernanke personally. The former academic, whose extraordinary decision-making during the financial crisis prevented a global crisis from turning into an unfathomable disaster, couldn’t even refinance his mortgage last year.

Meanwhile, plenty of his compatriots, many of whom performed their jobs with considerably less skill and verve, are already collecting their big payouts. Former Treasury Secretary Timothy Geithner works for the private equity firm Warburg Pincus; the former budget chief Peter Orszag is collecting checks from Citigroup; and former Fed governor Jeremy Stein is on the payroll at another hedge fund, BlueMountain Capital Management.

But just because Bernanke’s decision is understandable doesn’t make it right.

Following the debacle of “too big to fail” banks and other monetary institutions, official policy reform was supposed to create an economic climate in which the 2008 financial meltdown wouldn’t happen again. The reforms we got — Dodd-Frank and the Consumer Financial Protection Bureau — have curbed some of Wall Street’s worst practices, but not enough of them.

For example, high-frequency trading — of the sort that Bernanke’s new employer specializes in — has recently been ringing bells at the current Fed, because of the way it’s introduced new risks into the market for U.S. government bonds.

And it’s surely relevant that hedge funds remain largely unregulated by government institutions. One way that hedge funds maintain this special privilege is that they’re so good at hiring influential employees.

Finally, the cozy relationships between Wall Street and Washington can lead both of them to underestimate risky economic practices that have enormous potential impacts for the rest of us. We’ve just come through one of those terrible cycles. Unfortunately, it seems that this country won’t be able to depend on Bernanke to help us when the next one comes.